THE demise of the Warsaw Pact as a military force in international relations is probably the most momentous sequel to the East European revolution. To all intents and purposes, the Pact became a spent force the moment Poland initiated the revolution last year. Now it is fact.
The break from the alliance's military past was made by its top governing body, the Consultative Council, in Moscow last week. It was the Council's first meeting in a year. Its composition was an ironic comment from the Soviet viewpoint on all that has happened in Eastern Europe and in East-West relations since then.
Formerly, the Council included heads of state, together with ruling Communist Party, government, and military chiefs and their foreign ministers. All, of course, were communists.
This meeting was a metamorphosis. For the first time in 35 years, the Soviets had to deal with six equals. In addition, the Soviets were virtually the only communists at the Council table: Mr. Gorbachev was the only party chief, and he and Poland's Gen. Wojciech Jaruzelski were the only communist heads of state.
Romania and Bulgaria were represented by quasi-communists, though they presented reformist credentials. The other East Europeans were represented by noncommunists or anticommunists as diverse as Czechoslovakia's President Vaclav Havel and a pacifist East German defense minister.
After this meeting of the Warsaw Pact, its future - if any - must be said mostly to rest with NATO. Immediately after the event, the NATO foreign ministers went some way to offer a helping hand. They not only hailed the moves toward a ``transformation'' of the Pact. They also made tentative proposals for cooperation between the countries of both alliances in constructing a ``new Europe.''
In the broad sense, that is very consistent with Gorbachev's ideas. But his former allies showed they have their own views. Some - Hungary, for instance - are in a hurry to quit the alliance before 1992, the year of the West Europeans' single market.
Meantime, Soviet troop withdrawals from Czechoslovakia and Hungary continue. Poland, momentarily, hesitates over similar withdrawals until the security aspects of German reunification - specifically, guarantees for Poland's borders - are settled to its satisfaction. Here again, NATO will be the key factor.
Even so, Poland has already formally laid down a new defense concept: National forces exist to defend the nation, not outside alliances. In other words, the doctrine of mutual ``brotherly defense'' of ``socialism'' that Moscow invoked against the Czechs in 1968 is specifically excluded.
In general terms, the East Europeans are ready to give Gorbachev time and support for his ``pan-European'' ideas. But the East Germans, Poles, and Czechs have already circulated their own draft for a permanent standing council of the Conference on Security and Cooperation in Europe, bringing the nonaligned and neutral Europeans into its existing membership of 35 states.
Some of the East Europeans take the Western view that the best way to ensure against revival of past German ambitions is a unified Germany inside NATO. There is no support for Gorbachev's demand for a neutral Germany.
There is, however, some consensus for not immediately discarding the Pact but first modifying it into a political, consultative body able to negotiate with a similarly restructured NATO in working out the new formulas for all-European security. Proposals for the alliance's reorientation are due by the end of October.
The Bush-Gorbachev summit nudged things in that direction, though the security alignment of a single Germany - thorniest question of all in superpower relations - remained unresolved.
Following his summit success, however, Gorbachev may finally be persuaded that a united Germany within NATO's control is a less fearsome phenomenon than he has so far professed to fear. There will undoubtedly be strong pressures from the East Europeans to help him make up his mind.